1. Field of the Invention
The present invention relates to a polarizing plate and an optical laminate.
2. Description of the Related Art
A polarizing plate is arranged on each of both sides of the liquid crystal cell of a liquid crystal display apparatus as a typical image display apparatus. The arrangement results from the image-forming system of the apparatus. The polarizing plate typically includes a polarizing film and a protective film for protecting the polarizing film (for example, Japanese Patent No. 4751481 and Japanese Patent Application Laid-open No. 2003-149438). In association with a tendency toward the thinning of an image display apparatus in recent years, there has also been a growing requirement for the thinning of the polarizing plate to be used in the image display apparatus, and hence the thinning of each of the polarizing film and the protective film has been advancing. A technology involving using only one protective film for protecting the polarizing film has been proposed in relation to the thinning of the polarizing plate (for example, Japanese Patent No. 5332599). However, when the polarizing plate of Japanese Patent No. 5332599 is bonded to a display panel, a distance between the display panel and the polarizing film is large, and hence a problem occurs in that the display panel is liable to warp.
A cause for such warping of the display panel as described above is, for example, the deformation of the polarizing film (such as its expansion or contraction due to a temperature change). A reduction in concentration of boric acid in the polarizing film is conceivable as one means for reducing the deformation of the polarizing film. However, when the boric acid concentration is reduced, the following problem remarkably occurs. The durability of the polarizing film reduces, and in particular, when the polarizing film is thin, the polarizing film cannot be used under high temperature and high humidity.